• Journal of the Korean Vacuum Society
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• v.1 no.1
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• pp.50-59
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• 1992

By means of X-ray photoelectron spectroscopy(XPS), the initial stages of the oxidation of the cleaved CdTe (110) surface and the sputtered CdTe surface with oxygen exposure are invetigated. From the analyses of the spectra of Te 3dsn, Cd 3d5/2, 0 ls and Cd MNN Auger lines, it is shown that two oxygen atoms bond to one Te atom at the initial stages.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2003.10a
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• pp.293-298
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• 2003

The rockfall protection fences are installed to reduce rockfall damage in roads side slopes. The energy absorbing capacity of widely used rockfall protection fences is about 50kJ, But in many cases, rockfall protection fences are easily damaged even by a low level of rockfall energy. The objective of this paper is to verify the energy absorbing capacity of rockfall protection fences and investigate the behavior of them by rockfall. The LS-DYNA3D, a finite elements analysis program for dynamic movement of three dimensional objects, is used to perform the numerical simulations. In the result it is shown that rockfall protection fences absorb half of standard absorbing energy or less than it. It is inadquate for the rockfall protection fences to perform the principal function. To improve the performance of the fences, new rockfall proctection fence is proposed and numerical simulation is performed.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 2003.09a
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• pp.461-466
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• 2003

The rockfall protection fences are installed to reduce rockfall damage in roads side slopes. The energy absorbing capacity of widely used rockfall protection fences is about 50kJ. But in many cases, rockfall protection fences are easily damaged even by a low level of rockfall energy. The objective of this paper is to verify the energy absorbing capacity of rockfall protection fences and investigate the behavior of them by rockfall. The LS-DYNA3D, a finite elements analysis program for dynamic movement of three dimensional objects, is used to perform the numerical simulations In the result, it is shown that rockfall protection fences absorb half of standard absorbing energy or less than it. It is inadquate for the rockfall protection fences to perform the principal function. To improve the performance of the fences, new rockfall proctection fence is proposed and numerical simulation is performed.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.39 no.4
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• pp.259-269
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• 2013

In this work, licorice extracts were prepared using various extraction conditions such as extraction solvent, temperature, and time from Glycyrrhiza uralensis (G. uralensis) produced in Korea and China and Glycyrrhiza glabra (G. glabra) in Uzbekistan. The optimum extraction condition was selected from the extraction yields and antioxidative activities of extracts. Korea licorice extracts showed the highest free radical (1,1-diphenyl-2-picrylhydrazyl, DPPH) scavenging activity (46.05%) under the extraction condition of 85% ethanol at $60^{\circ}C$ for 6 hours. The prominent ROS (reactive oxygen species) scavenging activity using luminol-dependent chemiluminescence assay and the cellular protective effect against $^1O_2$ induced cellular membrane damage were also shown from the extracts obtained from the same condition. Especially, Korea G. uralensis extracts exhibited the higher prominent protective effect (${\tau}_{50}$ = 116.4 min) than (+)-(+)-${\alpha}$-tocopherol (${\tau}_{50}$ = 28.5 min) and the extraction yield of Korea licorice extract was 18.75%, which is 1.2 times and 2.5 times higher than that of Uzbekistan and China, respectively. These results indicate that the extraction condition of 85% ethanol at $60^{\circ}C$ for 6 hours is optimal to prepare licorice extracts, which can be applicable as anti-oxidative cosmetic materials.

• The korean journal of orthodontics
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• v.33 no.6 s.101
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• pp.475-483
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• 2003

The purpose of this study is to evaluate hard and soft tissue changes following the subapical osteotomy in bimaxillary dentoalveolar protrusion patients requiring maximal retraction adult female patients was selected. Surgical procedures were performed by the same surgeon, anterior subapical osteotomy techniques were employed on the maxilla and cephalometric radiograms were traced and superimposed using the best-fit method and two reference The results were as follows 1. The bodily movement of the maxillary anterior segment was achieved in a posterior moved posteriorly with a slight correction of the lower incisors. 2. The horizontal soft tissue measurements changed significantly after treatment, but Nt and Sn vertical soft tissue measurements indicated that Ls moved inferiorly and Li superiorly. 3. The correlation between hard and soft tissue changes indicated that ${\Delta}HId/{\Delta}HLi,\;{\Delta}HId/{\Delta}LL-Eline,\;{\Delta}Hpt.B/{\Delta}HILS,\;and\;{\Delta}UI-FH/{\Delta}NL$ were significant. 4. More lower lip relative to upper lip retraction was demonstrated in relation to Rickett's E-line. The ratio between upper lip displacement was $50\%$, and between the lower incisor and lower lip displacement was $60\%$. We conclude from the results that the anterior subapical osteotomy is an efficient treatment severe dentoalveolar protrusion and desire rapid results.

• Journal of Aquaculture
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• v.20 no.4
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• pp.226-231
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• 2007

We investigated survival and osmolarity, oxygen consumption, amonia extetion and filtration rates associated with physiological responses of the tunicate Halocynthia roretzi salinity changes. Acclimation times for osmolatity in different salinities took $20{\sim}26$ hours in 60% SW (19.8 psu) and $20{\sim}25$ hours in 80% SW (26.4 psu), while their times took $7{\sim}8$ hours in 110% SW (36.3 psu). Accordingly, acclimation times for high salinities were faster than those for low salinities. Survival (%) was more than 80% at salinity over 26.4 psu, and 6 $days-LS_{50}$ was 25.4 psu. physiological responses such as oxygen consumption, amonia excretion and filtration rates of H. roretzi showed more clear reactions in the longer exposure period (four days after exposure) than that in the beginning of the exposure. To sum up the results, the tunicate might be stressed from the beginning of the exposure in low salinity.

• Journal of KIISE
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• v.42 no.12
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• pp.1535-1543
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• 2015

The brain-computer interface obtains a user's electroencephalogram as a replacement communication unit for the disabled such that the user is able to control machines by simply thinking instead of using hands or feet. In this paper, we propose a feature extraction method based on a non-selected filter by SBCSP to classify motor imagery EEG. First, we divide frequencies (4~40 Hz) into 4-Hz units and apply CSP to each Unit. Second, we obtain the FLD score vector by combining FLD results. Finally, the FLD score vector is projected onto the optimal plane for classification using PCA. We use BCI Competition III dataset IVa, and Extracted features are used as input for LS-SVM. The classification accuracy of the proposed method was evaluated using $10{\times}10$ fold cross-validation. For subjects 'aa', 'al', 'av', 'aw', and 'ay', results were $85.29{\pm}0.93%$, $95.43{\pm}0.57%$, $72.57{\pm}2.37%$, $91.82{\pm}1.38%$, and $93.50{\pm}0.69%$, respectively.

• The Journal of Engineering Research
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• v.5 no.1
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• pp.73-87
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• 2004

The synthesis and crystallization of amorphous calcium carbonate($CaCO_3$.$nH_2 O$) obtained from gas-liquid reaction between aqueous solution of calcium hydroxide and carbon dioxide at 15~$50^{\circ}C$ are investigated by electrical conductometry, XRD and TEM. The results are as follows: The initial reaction products prior to the formation of precipitated calcium carbonate is amorphous calcium carbonate. The electrical conductivity values in the slurry are decreased during the formation of amorphous calcium carbonate which covers particle surface of calcium hydroxide and retard the dissolution of calcium hydroxide into the solution. that amorphous calcium carbonate is unstable in the aqueous solution and crystallizes finally to calcite by the through-solution reaction. While amorphous calcium carbonate crystallizes into chain-like calcite, the conductivity values are recovered rapidly and the apparent viscosity of slurry containing higher concentration of calcium hydroxide increase. At below pH 9.5, chain-like calcite separates into individual particles to form precipitated calcium carbonate. The formation and synthetic temperature range of amorphous calcium carbonate is most suitable a primary decreasing step(a-step) at $15^{\circ}C$ in the electrical conductometry.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.50 no.12
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• pp.829-838
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• 2022

This study conducts Hypervelocity Impact(HVI) simulations considering space objects with various shapes and different impact angles. A commercial nonlinear structural dynamics analysis code, LS-DYNA, is used for the present simulation study. The Smoothed Particle Hydrodynamic(SPH) method is applied to represent the impact phenomena with hypervelocity. Mie-Grüneisen Equation of State and Johnson-Cook material model are used to consider nonlinear structural behaviors of metallic materials. The space objects with various shapes are modeled as a sphere, cube, cylinder, and cone, respectively. The space structure is modeled as a thin plate(200 mm×200 mm×2 mm). HVI simulations are conducted when space objects with various shapes with 4.119 km/s collide with the space structures, and the impact phenomena such as a debris cloud are analyzed considering the space objects with various shapes having the same mass at the different impact angles of 0°, 30° and 45° between the space object and space structure. Although space objects have the same kinetic energy, different debris clouds are generated due to different shapes. In addition, it is investigated that the size of the debris cloud is decreased by impact angles.

• Journal of the Korean Society of Food Science and Nutrition
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• v.33 no.1
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• pp.107-113
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• 2004

This study explored the association between the bone nutrition indicators and the bone mineral density (BMD) in 138 apparently healthy elderly (male: 38, female: 100) dwelling in a low income area of the city. Dietary intakes were estimated from two meals (breakfast ＆ dinner) and snack using 24 hr-recall method and lunch with weighing over 3 consecutive days. Female elderly showed significant lower intakes (p<0.001∼p<0-05) for most of the nutrients except calcium and vitamin C than the elderly male. Calcium and vitamin D intakes for both male and female were 331.0 mg, 1.89 $\mu\textrm{g}$ and 308.6 mg, 1.21 $\mu\textrm{g}$, respectively and they were below the 50% of the RDA. Both the BMDs at lumbar spine (LS) and femoral neck (FN) were positively correlated with the energy intake, calcium intake and vitamin D intake (p<0.05, respectively) for male. In female BMDs of the both sites were positively correlated with the intakes of carbohydrates, protein, lipid, calcium and vitamin D (p<0.01∼p<0.05). Female showed higher serum osteocalcin (p<0.01) and urinary deoxypyridinoline/creatinine (DPYR/CR) (p<0.001), meaning that female had elevated rate in bone turn over and bone resorption. The proportion of subjects with vitamin D deficiency assessed with serum 25(OH)VitD$_3$<10 mg/mL was 35.0% for female and 23.7% for male, respectively Both the BMDs at lumbar spine and trochanter were positively correlated with serum 25(OH)VitD$_3$ but BMDs in most of the sites were negatively associated with urinary DPYR/CR, phosphate/CR. Stepwise multiple regression showed physical activity, serum alkaline phosphatase, weight, vitamin D explained 47.6% of the variation of the LS BMD. The indicator variable for serum alkaline phosphatase was negatively associated with LS BMD. However, the indicator variable for weight and vitamin D intake were positive and significant (p=0.0087, p=0.0007, respectively). For FN BMD, the indicator variable for age and serum alkaline phosphatase were negative and significant (p<0.0075, p<0.0015, respectively) and the weight was positively associated with the FN BMD.